While many types of vehicles utilizing internal combustion engines powered by gasoline utilize fuel injection systems to deliver and meter the necessary air-fuel mixtures, other types of vehicles as for example, vehicles used in auto racing use carburetors for delivering and metering the necessary air-fuel mixtures.
These carburetors contain therein one or more float bowls that acts as a reservoir for the fuel, typically gasoline. Each bowl requires some type of air venting mechanism in order for the carburetor to draw fuel from the reservoir. If the bowl is not vented to the outside atmosphere, a vacuum will be created that will prevent the carburetor from properly drawing fuel. One method for venting is to install one or more vent tubes into the top of the bowl that normally extend vertically upward. Each tube is open at its upper end.
During normal vehicular operation, this carburetor arrangement functions properly. However, under extreme conditions such as auto racing, vehicles can become unstable and turn partially or completely over. Under these conditions, the tube can be rotated to an angle in excess of ninety degrees. The gasoline in the bowls then leaks out of the tubes. A vehicle so rendered unstable during a race has an extremely hot exhaust system. The leaking gas can engage the exhaust system and create dangerous fires.
It is an object of the present invention to provide a new and improved carburetor structure in which gasoline cannot leak out of carburetor vent tubes when disposed horizontally or vertically whereby the danger of leaking gas is eliminated.
Another object is provide in each fuel bowl a check valve mechanism connected to the vent tube which allows normal carburetor operation when the tube is disposed vertically but prevents fuel leakage out of the tube when the tube is disposed at an angle greater than ninety degrees from the vertical.
Yet another object is to provide a new and improved carburetor structure of the character indicated that can be manufactured easily and inexpensively.
These and other objects and advantages of the invention will either be explained or will become apparent hereinafter.
In accordance with the principles of this invention, a normally vertical vent tube open at its upper end is connected at its open lower end by a horizontal air conduit to the top of a fuel bowl. The lower end has a recess in which is mounted a check valve mechanism. When the tube is in its normally vertical position, the mechanism permits the air venting function of the tube to operate in the normal manner. However, when the tube is oriented at an angle greater than ninety degrees from the vertical, then mechanism seals off and blocks the air venting mechanism, thus preventing the fuel leakage and eliminating danger of fire.
The mechanism can be a sphere having a diameter somewhat larger than that of the inner diameter of the tube. During normal operation, the sphere rests in the recess and is spaced from the lower end of the tube. When the tube is tilted to an angle greater than ninety degrees from the vertical, the sphere engages the lower end of the tube, blocking air flow therethrough and preventing gasoline leakage discharge.